The semiconductor integrated circuit (IC) industry has experienced rapid growth. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs.
However, when a semiconductor device such as a metal-oxide-semiconductor field-effect-transistor (MOSFET) is scaled down through various technological nodes, device density and performance are challenged by the device layout and needed isolation. As the demands for circuit density increase, one area under study has been the implementation of a continuous active region. A continuous active region can reduce the need for insulating structures, thus, allowing for a reduction in die size, a reduction of stress on the substrate, and/or a reduction of current penalties attributable to the isolation structures. However, layout changes such as continuous active regions provide other challenges such as providing sufficient isolation between adjacent devices and maintaining device performance.
Therefore, existing methods and devices for improving isolation in semiconductor devices have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects.